Kidney cancer is cancer that originates in the kidneys. Your kidneys are two bean-shaped organs, each about the size of your fist. They're located behind your abdominal organs, with one kidney on each side of your spine. In adults, the most common type of kidney cancer is renal cell carcinoma. Other less common types of kidney cancer can occur. Transitional cell carcinoma, which affects the ureters, can also begin in the kidneys. Children are more likely to develop a kind of kidney cancer called Wilms' tumor.

Causes of Kidney Cancer

It's not clear what causes renal cell carcinoma. Doctors know that kidney cancer begins when some kidney cells acquire mutations in their DNA. The mutations tell the cells to grow and divide rapidly. The accumulating abnormal cells form a tumor that can extend beyond the kidney. Some cells can break off and spread (metastasize) to distant parts of the body.

Signs & Symptoms of Kidney Cancer

Kidney cancer rarely causes signs or symptoms in its early stages. In the later stages, kidney cancer signs and symptoms may include:

Removing a sample of kidney tissue (biopsy). In very selected cases, your doctor may recommend a procedure to remove a small sample of cells (biopsy) from a suspicious area of your kidney. Because surgery is usually the first line treatment for kidney cancer and a kidney biopsy carries the risk of a "false-negative," doctors usually forgo kidney biopsy. Kidney biopsy is typically reserved for cases that are most likely to be noncancerous or for people who can't undergo an operation.

Kidney cancer staging

Once your doctor diagnoses kidney cancer, the next step is to determine the extent, or stage, of the cancer. Staging tests for kidney cancer may include additional CT scans or other imaging tests your doctor feels are appropriate.

Then your doctor assigns a number, called a stage, to your cancer. Kidney cancer stages include:

Stage I. At this stage, the tumor can be up to 2 3/4 inches (7 centimeters) in diameter. The tumor is confined to the kidney.

Stage II. A stage II kidney cancer is larger than a stage I tumor, but is still confined to the kidney.

Stage III. At this stage, the tumor extends beyond the kidney to the surrounding tissue or the adrenal glands, and may also have spread to a nearby lymph node.

Stage IV. Cancer spreads outside the kidney, to multiple lymph nodes or to distant parts of the body, such as the bones, brain, liver or lungs.

Treatments of Kidney Cancer

Together, you and your treatment team will discuss your kidney cancer treatment options. The best approach for you may depend on a number of factors, including your general health, the kind of kidney cancer you have, whether the cancer has spread and your preferences for treatment.

Surgery

Surgery is the initial treatment for the majority of kidney cancers. Surgical procedures used to treat kidney cancer include:

Removing the affected kidney (nephrectomy). Radical nephrectomy involves the removal of the kidney, a border of healthy tissue and the adjacent lymph nodes. The adrenal gland may also be removed if it appears the tumor has grown into the gland. Nephrectomy can be an open operation, meaning the surgeon makes one large incision to access your kidney. Or nephrectomy can be done laparoscopically, using several small incisions to insert a video camera and tiny surgical tools. The surgeon watches a video monitor to perform the nephrectomy.

Removing the tumor from the kidney (nephron-sparing surgery). During this procedure, also called partial nephrectomy, the surgeon removes the tumor and a small margin of healthy tissue that surrounds it, rather than removing the entire kidney. Nephron-sparing surgery can be an open procedure, or it may be performed laparoscopically. Nephron-sparing surgery may be an option if you have a small kidney cancer or if you only have one kidney. When nephron-sparing surgery is possible, it's generally preferred over radical nephrectomy, since retaining as much kidney tissue as possible may reduce your risk of later complications, such as kidney disease.

The type of surgery your doctor recommends will be based on your cancer and its stage, as well as your health. Surgery carries a risk of bleeding and infection.

Treatments when surgery isn't possible For some people, surgery may be too risky. These people have other options for treating their kidney cancers, including:

Blocking blood flow to the tumor (embolization). In this procedure, a special material is injected into the main blood vessel leading to the kidney. Clogging this vessel deprives the tumor of oxygen and other nutrients. Arterial embolization also may be used before an operation or to relieve pain and bleeding when an operation isn't possible.

Treatment to freeze cancer cells (cryoablation). During cryoablation, a special needle is inserted through your skin and into your kidney tumor using X-ray guidance. Gas in the needle is used to cool down or freeze the cancer cells. There are few long-term data about the safety and efficacy of cryoablation. It's typically reserved for people who can't undergo other surgical procedures and those who have small kidney tumors located in areas that can be easily reached with a needle.

Treatment to heat cancer cells (radiofrequency ablation). During radiofrequency ablation, a special needle is inserted through your skin and into your kidney tumor using X-ray guidance. An electrical current is run through the needle and into the cancer cells, causing the cells to heat up or burn. There are few long-term data about the safety and efficacy of radiofrequency ablation. Radiofrequency ablation may be an option for people who can't undergo other surgical procedures and those with small kidney tumors located in areas that are easily reached with a needle.

Treatments for advanced and recurrent kidney cancer Kidney cancer that recurs and kidney cancer that spreads to other parts of the body may be curable. In these situations, treatments may include:

Surgery to remove as much of the kidney tumor as possible. Even when surgery can't remove all of your cancer, in some cases it may be helpful to remove as much of the cancer as possible.

Drugs that use your immune system to fight cancer (biological therapy). Biological therapy (immunotherapy) uses your body's immune system to fight cancer. Drugs in this category include interferon and interleukin-2, which are synthetic versions of chemicals made in your body. Side effects of these drugs include chills, fever, nausea, vomiting and loss of appetite.

Treatment that targets specific aspects of your cancer (targeted therapy). Targeted treatments block specific abnormal signals present in kidney cancer cells that allow them to proliferate. These drugs have shown promise in treating kidney cancer that has spread to other areas of the body. The targeted drugs bevacizumab (Avastin), pazopanib (Votrient), sorafenib (Nexavar) and sunitinib (Sutent) block signals that play a role in the growth of blood vessels that provide nutrients to cancer cells and allow cancer cells to spread. Temsirolimus (Torisel) and everolimus (Afinitor) are targeted drugs that block a signal that allows cancer cells to grow and survive. Targeted therapy drugs can cause side effects, such as a rash that can be severe, diarrhea and fatigue.

Chemotherapy. Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. Chemotherapy isn't commonly used to treat renal cell carcinoma. But chemotherapy may be used to treat transitional cell carcinoma — a cancer of the ureters that sometimes begins in the kidneys. Chemotherapy treatments may be used before surgery to shrink a tumor, making it easier to remove. Or chemotherapy may be used to treat cancer cells that have traveled to distant parts of the body.

Treatments for distant tumors. Kidney cancer cells that travel to other parts of the body (metastasize) can sometimes be treated. This depends on the number of distant tumors, their locations and your general health. Treatment options vary based on where your cancer has spread. Options might include surgery for brain metastasis or radiation for kidney cancer that has spread to bones.

Clinical trials. Clinical trials are studies of new treatments and new techniques for treating kidney cancer and other diseases. Participating in a clinical trial may give you a chance to try the latest treatments, but it can't guarantee a cure. Discuss the available clinical trials with your doctor and carefully weigh the benefits and risks. Some kidney cancer clinical trials are studying new and existing targeted therapies to determine the best ways to use this new class of drugs.

Quit smoking. If you smoke, quit. Many options for quitting exist, including support programs, medications and nicotine replacement products. Tell your doctor you want to quit, and discuss your options together.

Eat more fruits and vegetables. Add more fruits and vegetables to your diet. A variety of fruits and vegetables helps ensure that you're getting all the nutrients that your body needs. Replacing some of your snacks and side dishes with fruits and vegetables may help you lose weight.

Maintain a healthy weight. Work to maintain a healthy weight. If you're overweight or obese, reduce the number of calories you consume each day and try to exercise most days of the week. Ask your doctor about other healthy strategies to help you lose weight.

Control high blood pressure. Ask your doctor to check your blood pressure at your next appointment. If your blood pressure is high, you can discuss options for lowering your numbers. Lifestyle measures such as exercise, weight loss and diet changes can help. Some people may need to add medications to lower their blood pressure. Discuss your options with your doctor.

Reduce or avoid exposure to environmental toxins. If you work with toxic chemicals, take special precautions such as wearing a mask and heavy gloves. In the United States, your employer is required to tell you what chemicals you may be exposed to on the job. Follow your employer's safety procedures, and ask your doctor if there are other ways to protect yourself from chemical exposure.

When to seek Medical Advice

Make an appointment with your doctor if you have any persistent signs or symptoms that worry you.